Hydrogenation reactor is commonly used in the hydrogenation processes of coal chemical industry and petrochemical industry. Hydrogenation reactor can be divided into two categories, a “hot-wall” reactor and a “cold-wall” reactor, depending on the temperature of its shell. The hot wall reactor does not have an inner heat-insulation layer, so that the difference between the cylinder wall temperature and the internal reaction temperature is small; a cold-wall reactor has an internal heat insulation layer, under which the temperature of cylinder wall temperature is far lower than that of the internal reaction.
The wall temperature of hot-wall reactor uniformly distributes and does not easily generate local overheating, which can improve the safety of use. However, with the development of heavy oil hydrogenation technology and the success of establishing first set of self-developed super suspension bed hydrogenation technology in China, the design temperature of suspension bed hydrogenation reactor is continuously raised, even up to 500° C., which has greatly exceeded the maximum using temperature (482° C.) of conventional anti-hydrogen corrosion steel in China and abroad. Thereby conventional hot-wall reactor is not suitable for ultra-high-temperature hydrogenation process.
Due to the relatively low temperature of the barrel wall of the cold-wall reactor, it can be applied to the working condition in which the internal reaction temperature is higher than the maximum temperature limit of the barrel wall materials. The conventional cold-wall reactor comprises a reactor body and a support seat. Furthermore, the reactor body comprises a vertically arranged cylinder body as well as an upper sealing head and a lower sealing head that are connected to the top and bottom of the cylinder body, respectively. The upper sealing head is provided with a discharge pipe, and the lower seal head is provided with a feeding pipe. From outside to inside, the structure of the cylinder body, the upper seal head and the lower seal head sequentially comprises: a metal shell, a stainless steel surfacing layer, a thermal insulation liner and a inner liner cylinder. The thermal insulation liner comprises an insulating firebrick layer clinging to the inner wall of the stainless steel resurfacing welding layer and a heat insulation packing layer clinging to the outer wall of the inner liner cylinder. The inner liner cylinder is connected with the metal shell and is fixed in the center of the reactor. For example, for a suspended bed hydrogenation cold-wall reactor with a design temperature of 500° C. and a design pressure of 23 Mpa, the material of the metal shell is typically 2.25Cr−1Mo −0.25V steel with a thickness of about 100 mm to 200 mm, the material of the stainless steel resurfacing welding layer is TP309+TP347 with a thickness of about 7 mm to 10 mm, the material of the thermal insulation liner is Al2O3+CaO with a thickness of about 100 mm to 150 mm and the material of the inner liner cylinder is SS321 with a thickness of about 7 mm to 10 mm.
Thus, conventional hydrogenation cold-wall reactor still has the following problems: 1. in the same profile dimensions, the effective volume of the reactor is small which impact the productivity. To reach the same productivity, the overall size needs to be increased, which increases the difficulty of manufacture and the investment cost of equipment. 2. Due to the relatively thick thermal liner, the design, manufacture and construction of the cold-wall reactor are more complicated, and the inner wall examination is also very inconvenient. Furthermore, the thermal insulation liner is easily damaged in actual working conditions, resulting in infiltration/flow of the hot fluid onto the wall and localized ultra-temperature on metal shell. This would compromise the safety production or forced shutdown. 3. Due to the fixed connection between the inner liner cylinder and the outer shell, when any flaws presented in the construction process or design, the connection part will expand and contract at the operating temperature which leads to concentration of local stress on the outer shell body. This causes potential safety hazards.